Presently, power delivery to integrated circuits (ICs), such as a microprocessor or a central processing unit (CPU), within an electronic device, such as a computer, relies on a buck voltage regulator. This type of regulator usually has low efficiency at light loads and only performs well at high loads. In ultra-mobile computing platforms, where loads may be very light, buck-type regulators may frequently operate well below their peak (maximum) efficiency.
As electronic devices trend toward power reduction and simultaneous integration of more diverse features, the power delivery network must provide power at a number of different voltage levels for different of interfaces and functionalities. These interfaces may be on a single component, such as IC 106, or distributed across multiple components/ICs. For example, as depicted in FIG. 1, mobile computing device 100 includes a motherboard 105 which supports a chipset requiring at least three different regulated voltage rails. This is achieved in stages with a voltage regulator (VR) 110 to regulate a power supply, such as Li-ion cell(s) 106 to a first voltage level of 3V. VR 110 accommodates the range of voltages a Li-ion battery may output throughout various levels of discharge (e.g., 4.2V-4.8V/cell). As further shown, point of load (POL) voltage regulators coupled with VR 110 then provide a second stage of power delivery for each of any number of output load circuits on the motherboard 105. For example, VR 111 provides a 1.3V rail to memory 140, VR 112 provides a 1.75V rail to a Serial Advanced Technology Attachment (SATA/100, SATA/300, SATA/600 etc.) compliant interface 145 and VR 113 provides 2.3V to PCI Express chipset (PCIe v1.1, PCIe 2.0, etc.) 150. With additional POL voltage regulators potentially required for a Universal Serial Bus (USB 1.1, 2.0, 3.0, etc.), a processor unit, etc., the area of motherboard 105 consumed by voltage regulators may approach 40%.
Correspondingly, a need exists for a readily scalable power delivery network which can be operated efficiently over a range of loads and can be integrated into a smaller form factor.